Overarm for milling machines



Dec. 27, 1927. 1,653,846

B. P. GRAVES OVERARM FOR MILLING MACHINES Filed June 16, 1925 a z? 65 0 mwm/wm Patented Dec. 27, 1927.

BENJAMIN P. GRAVES, F CRANSTON, RHODE. ISLAND, ASSIGNOB T0 BROWN AND SHARPE MANUFACTURING COMPANY, A CORPORATION OF RHODE ISLAND,

OVER-ARM FOR MILLING MACHINES.

Application filed June 16, 1925. Serial No. 37,505.

The overarm commonly used in milling machines consists of a cylindrical bar adjustably clamped in the upper portion of the machine column in a bearing parallel to the spindle. The advantages of this form of overarm are well recognized. The principal object of the present invention is to provide an overarm structure for milling machines which shall retain the valuable features of this form of arm while aifording a much more rigid support for the outbearing hanger, or arbor yoke. Other objects of the inven'tionare to provide an overarm structure of simple and improved construction capable of rigidly supporting the arbor yoke so as to prevent any possibility of misalignment of the arbor under the thrust of the milling cutters even on the heaviest work for which the machine is designed.

bodied in an overarm structurecomprising a cylindrical bar functioning mainly as a centering and supporting unit for the arbor yoke, or for the various attachments used on the machine, and a substantially semi-cylindrical cap member engaging the arbor yoke so as to brace the yoke againstthe thrust of the cutters, which cap member overlies and embraces the cylindrical bar .and is clamped or otherwise secured at its rear end 'to the bar. The cylindrical bar and cap member thus form a single compound arm which can be adjusted as aunit with relation to the machine column, and also by dis connecting the cap member from the cylindrical bar the bar can be used alone in the same manner as the form of arm commonly used, and with the same attachments. It is to be understood, however, that certain 40 features of the present invention in their broaderaspects are not limited to an overarm construction which comprises acylindrical bar, or to a' construction in which the cap member or arbor 46 is secured to the bar.

The several features of the present invention will be readily understood byv those skilled in the art from the following description taken in connection with the accom- 50 panying drawings which illustrate an'overarm construction embodying the invention in its preferred form.

Referring to the drawings, Fig. 1 is a View in side elevation of the upper portion of the column of a milling machine of well-known The invention is herein shown as em-V is indicated at 7.

yoke bracing member construction with the improved overarm proved construction for connecting an arm brace to the over-arm at the outer end of the arm; Fig. 31s a sectional view on the line 3-3 of Fig. 1 illustrating particularly the manner in which the cap member is supported and guided upon the machine column; and Fig. 4 is a sectional view on the line 4-4 of Fig. 1 illustrating particularly the mechanism for adjusting the overarn'i tb cause it to project more or less beyond the face of the column and the mechanism for clamping the cylindrical bar of the overarm structure in adjusted posit-ion.

As has been stated, the improved ovcrarin structure herein shown comprises a cylindrical bar which serves as centering and supporting unit for the arbor yoke and a cap member which engages the arbor yoke and acts as a bracing member for the yoke, The cylindrical bar is indicated at l and is, or may be, identical as to size and location with the cylindrical overarm con'unonly used on this type of machine. The bar engages hearings in the upper end of the machine column through which it may be adjusted longitudinally and by which it is maintained in accurate alignment with the spindle of the machine. The bar is locked in adjusted position by clamping bolts 2 and 3; and to enable these bolts to be readily manipulated by the operator the bolt 3 is provided with a hand lever 4, and this lever is connected by a link 5 to an arm 6 connected to the bolt 2.

Thecap member of the overarm structure This member is substantially semi-circular, or semi-elliptical, in cross'section and overlies and partially encloses the cylindrical bar and fits" over the top of the column. At its rear end the cap member is secured to the cylindrical bar 1 by a clamping bolt 8, and throughout substantially itsfront half portion it is provided at its lower edges with horizontal bearing surfaces which are arranged to rest and slide upon horizontal bearing surfaces. formed on the column at the upper portion of the face 9 of the column and on lugs 10 projecting laterally from the column back of the face. The lower edges of thel'ront portion of the cap member are provided with T-shaped slots 11, and these slots are engaged by T bolts 12 which project through the lugs 10 on the column and securely and rigidly clamp the cap memberto the column. An arbor yoke is indicated at 1?; and is provided with the usual bearings 14 and 15 l for the cylindrical bar of the overarm and for the cutter arbor. The arbor yoke is formed with a split clamp, and a clamping bolt 16 is provided by which it may be se cured in position on the cylindrical bar.. The arbor yoke formed with projections, or ears, extendinglaterally onealch side of the cylindrical bar 1 and beneath the horizontal bearing surfaces on the lower edges of the cap member 7. These lateral projections of the arbor yoke at their upper sides are provided with horizontal bearingsurfaces which fit snugly against the horizontal bearing surfaces on the cap member. The bearing surfaces on the cap member are parallel with the axis of the cylindrical bar, and thus the arbor yoke is engaged and braced by these bearing surfaces in all positions of adjustment with relationto the lace ofthe column. It will be noted that the cylindrical bar of the overarm structure can be securely clamped to; the column of the machine and that the cap member, in addition to being clampedto the cylindrical bar, can be securely bolted to the machine column. The two members of the overarm structure being clamped together and being fastened to the machine columnindividually, afford an un usually rugged support for the arbor yoke which is amply strong enough to resist the stress of any out within the capacity of the machine. The arbor yolie can notonly be clamped to the cylindrical bar 1, but also T-shaped bolts may be provided passing through the ears ofthe arbor yoke and engaging the T slots in the cap member, by which the arbor yoke may be firmly bolted to the cap member. This greatly increases the rigidity of the arbor yoke and more effectiyely resists any tendency of misalignment of the arbor caused by the thrust of the cutters.'

The great rigidity which is provided for the arbor yoke and arbor by the improved overarm construction of the present invention makes it possible to operate the machine satisfactorily without an arm brace when necessary or desirable. lVhen an arm brace is used the form illustratedin Figs. 1 and 2 provides an extremely rigid and ellicient construction which takes advantage of the rigidity of both the cylindrical bar and the cap I iece. To secure this result, the arms or members of the brace areconnected to both the bar and the cap piece through a second arbor yoke .17 similar to the arbor yoke 13 and secured in the same way to the bar and cap piece near their outer ends. This. arbor yoke is provided with perforated bosses to receive clamping bolts 20 fwhich pass through slots in the arms 21 ot the brace and through these bosses.

To enable the overarnr structure to be quickly and easily adjusted, the cylindrical bar I proyided on the bottom near its rear end with a rack 18 which is engaged by a pinion shaft 19 journaled in the machine column below and at rip'h-t angles to the bar.

The outer end o'l this pinion shaft is squared to adapt t to receive a hand crank; As

will be obvious to adjust the entire one! arm structure it is merely necessary to loosed the clamping bolts 12 and rotate the pinion shalt Tl1e cylindrical bar 1 can be adjustcd individually by loosening the clamp ing bolt 8 which secures the cap piece to the bar and then rotating the pinion shaft.

Attachments designed for use only witl r a cyhndrlcal oyerairin can be usedona-ma chine equipped with the improved oyerarm structure of the present invention by setting the cap member back out or position. and adjusting the cylindrical bar so as to permit the attachment to be fastened" to it.

hen attachments are to be used that must be bolted to the colummor when large face milling cutters are to be used, the complete overarm structure can be run bacl until flush with the face or the column and the at r tachment or cutter mounted on the machine in the usual manner.

what is claimed is;

The invention having been thus described; g l o 1. The combination; with the column. of a. milling. machine of an oterarm compris ng, a cylindrlcal bar ad -ustably securedqm the column, an arbor yoke. mounted on the bar,

an arboryokebracing memberforrnin part 5 of the overarm engagmg the arbor yoh e and secured to the forward part; of the column; and means ror securing said member at its rear end tothe bar.

E2.- The combination with t a domain of a milliug machine of, an oyerarin comprising a longitudinally adjustable barmounted iiithe column, a longitudinally adjustable yoke bracing cap member overlyin the bar,

means for securing the cap to tie forward 1 part or the column and at its resend to. the bar, and an arbor yoke mounted on the bar prot ided with laterally rejeeunpyears underlying and engaging the under er gas (if the cap member.

a The combination with: the dammit" tr a izo milling machine of an overalls comprising a...

cylindrical ha adjustably mounted in the. column, an arbor yoke mounted on the bar, ii the an arboryoke b 'acin fmeinber agagm arbor yoke, means In adjustably [s the member tothe forward part oi tl umn, and means for dctachably securing said member at its rear end to the bar to;

permit a simultaneous adjustment of said member and bar or an independent use of the bar.

4. The combination with the column of a milling machine of an overarm comprising a longitudinally adjustable cylindrical bar mounted in the column, a substantially semicylindrical longitudinally adjustable cap iece overlying the bar and provided with caring surfaces parallel to the axis of the bar, an arbor yoke mounted on the bar provided with bearing surfaces engaging the bearing surfaces on the cap piece, means for adjustably securing the cap piece to the forward part of the column, and means for seguring the cap piece at its rear end to the ar. t

5. The combination with the column of a millingmachine of an overarm comprising a cylindrical bar mounted in the column, a substantially semi-cylindrical cap piece overlying the bar and secured at its rear end to the bar, said cap piece being provided on its lower edges with bearing surfaces parallel to the axis of the bar arranged to engage bean ing surfaces on the column, means provided at the forward part of the column for clamping together the bearing surfaces of the cap member and the column, and an arbor yoke mounted on the bar provided with laterally projecting ears underlying and engaging the bearing surfaces on the cap piece.

In testimony whereof I have signed my name to this specification.

BENJAMIN P. GRAVES. 

